Some embodiments relate to a device for measuring an electric current generated by an acoustic amplifier in order to actuate an acoustic speaker.
In the field of electroacoustics and, more particularly, of generating sound by converting an electrical signal to an acoustic wave through the use of speakers, it is important to have precise knowledge of the electric current consumed by these speakers, i.e. the instantaneous current of the electrical signal supplying power to the speakers.
Specifically, as for any energy conversion, this electrical-to-acoustic conversion generates heat and it is therefore necessary to verify that the heat generated remains below a predetermined threshold. This parameter is particularly important in professional speakers intended to fill large spaces with sound, since the amounts of energy used are substantial. The dissipated power is proportional to the square of the RMS amplitude/current of the electrical signal. Thus, knowing how much current is consumed makes it possible to work out the dissipated power and hence how much heat is emitted.
This precise knowledge of the current also has other applications, such as precise knowledge of the impedance of the speakers as a function of the frequency and the detection of the loudspeakers.
In order to measure this electrical signal current, related art techniques use a specialized differential amplifier including a resistor at input (a shunt for measuring the current) allowing a current to be converted to a potential difference.
However, this type of current detection amplifier is intrinsically sensitive to the common mode voltage present on the measurement shunt and therefore necessitates the use of a costly high-precision differential amplifier if the levels of precision required in electroacoustics are to be attained.